The present invention pertains to a plug-type connector module carrying a printed circuit board and, in particular, a plug-type connector having a plurality of plug elements which are connected to a printed circuit board mounted thereon.
Plug-type connector modules are used, for example, in the electronic fuel injection systems of automobiles, where the mixture enrichment during start, warm-up and acceleration is controlled electronically. The air-fuel ratio is influenced by means of a start flap. A second actuator on the throttle valve provides for the correct charging. A so-called throttle valve potentiometer which is connected with the throttle valve shaft by means of a coupling is used to indicate the position and the movement of the throttle valve. The printed circuit board of the plug-type connector module essentially consists of a potentiometer with a resistor strip located between two terminals and a parallel collector strip, both of which are contacted with a sliding contact. The voltage is supplied and the tapped voltage is transmitted to the electronic system by means of a plug-type connection. A device of this general type for detecting the operation of a throttle valve of a carbureator is described in West Germany patent publication DE-PS No. 3,029,321. A throttle valve which is connected with the sliding contact of a potentiometer is located in the suction channel of the carbureator. The tapped voltage is sent via an amplifier to two scanning and interception circuits which in turn are connected with an operation amplifier comparator. The output voltage is an indicator of the angular velocity of the throttle valve. When the throttle valve stops or rotates in the plug-type connector module-site direction, the output voltage of the comparator disappears.
A throttle valve potentiometer is already known which consists of a plastic insulating body which carries a ceramic plate with a resistor strip and with a collector strip as an applied printed circuit. A plug connector part is injection molded in the insulating body. This part consists of a projecting plug member and a rear contact member which serves the purpose of electrically connecting the plug member with the printed circuit. The plug member is a flat plug or a round plug made of dimensionally stable material. However, the contact member consists of a relatively soft spring material. One of the ends of the contact member is welded to the flat plug, from which the material of the insulating body is injection-molded around it. The other end of the contact member fits into perforations of the ceramic substrate and is soldered there by hand to edge contact points. When a round plug is used, the contact member is inserted into a centric cavity of the round plug, soldered at the free end and subsequently ground off, which is relatively labor-intensive. The contact member also has an arc-shaped deformation in order to better compensate the differences in the expansion of the material under the effect of temperature variations. Since the contact member consists of a relatively soft spring material, difficulties can arise due to unintended bending of the contact member during the injection-molding process. The manual soldering of the contact member to the edge contact points in the perforations is a source of contact uncertainty which is manifested in a higher failure rate.
The insulating body consists of a base with a flat first surface. From this surface rises a table mountain-like carrier part on whose second surface the printed circuit is disposed. The second surface or the printed circuit should lie as exactly parallel to the first surface as possible. However, since the insulating body is made of plastic, it is subject to the ordinary technological shrinkage tolerances which are dependent on the shape of the body. Measurements have shown that the deviations amount to more than 100 um (microns). In addition, the ceramic plate of the printed circuit is not perfectly flat either. However, the tolerances here are only about 10 um. The printed circuit is held in place on the carrier part by an adhesive. This adhesive has the property of contracting due to shrinkage, such that mechanical stress is generated in the printed circuit. It should be borne in mind in this connection that the range of application can extend to as high as 150.degree. C. Since the second surface is not exactly parallel to the first surface, and since the surface of the printed surface is aligned to the first surface, it may occur that the printed circuit fits snugly on the carrier part in one area of the first surface, while in another area it may have a gap in excess of 100 um. Even though this is compensated by a thicker adhesive layer, the adhesive mass does not harden but must follow the temperature variations. It can also happen that the adhesive mass is squeezed out and causes contamination in the areas where the printed circuit fits the carrier part snugly.
A soldered tab for printed circuits whose end is shaped as a clamp is already known from West Germany patent publication DE-OS No. 2,849,610. At the edge this clamp is pushed onto the printed circuit. Part of the clamp carries a solder globule which melts under the action of heat and establishes electrical connection between the solder tab and the edge contact point of the printed circuit. The solder tabs are attached to a one-piece perforated band. After the solder tabs are soldered, the sliding contact is cut. A conductor can subsequently be soldered to the perforations.